This proposal concerns a 4-year systematic vaccine development program utilizing 4 naturally occurring retrovirus diseases, feline leukemia virus (FeLV) infection of domestic cats, simian-AIDS retrovirus, type 1 (SRV-1) and Sooty mangabey lentivirus (SMLV) infections of rhesus monkeys, and caprine arthritis-encephalitis virus (CAEV) infection of dairy goats. The main objective of the project is to compare the effectiveness of proven and unproven vaccine strategies on a diverse group of animal retroviral diseases. In keeping with our previous research approaches, studies will begin with conventional inactivated whole virus vaccines, followed by native envelope glycoprotein, recombinant/subunit envelope protein, synthetic peptide, genetically engineered vaccinia virus, and anti-idiotype antibody vaccines. The vaccine strategies applied to each of the retrovirus infections varies according to the amount of background research already completed in that system. Anti-idiotype antibody vaccines will be tested in the FeLV system, because conventional and molecular-genetic approaches have already been tested. Research on inactivated whole SRV-1 vaccines has already been completed, so work on this disease will be directed to native envelope-glycoprotein, recombinant/subunit, synthetic peptide, genetically altered vaccinia virus, and anti-idiotype antibody vaccines. Work on SMLV and CAEV infections will be more developmental and directed at basic pathogenesis and inactivated whole virus vaccines.